1. Field of the Invention
The present invention relates to a semiconductor gas sensor and to a method for measuring a residual gas proportion with a semiconductor gas sensor.
2. Description of the Background Art
DE 199 12 100 A1, which corresponds to U.S. Pat. No. 6,890,422, discloses an electrochemical gas sensor, which responds to oxidizable gas components such as CO, for example, and hereby however does not catalytically change the establishment of equilibrium of a gas mixture that contains oxygen. A platinum/gold alloy with a gold proportion in a range between 0.5% to 20%, preferably with a gold proportion of 10% is used for the measuring electrode. The operating temperature of the sensor is approximately 500° C.
A semiconductor gas sensor embodied as an HSGFET (Hybrid Suspended Gate FET) for the detection of ozone is known from the printed publication “M. Zimmer et al., Gold and platinum as ozone sensitive layer in work-function gas sensors, sensors and actuators, B80 (2001) 174-178.” It has been shown that a platinum electrode has no sensitivity to carbon monoxide. In contrast to the electrochemical sensors, with the HSGFET sensors or the SGFET sensors a detection of gases takes place via a change of the work function at the gas-sensitive layer. Sensors of this type are operated in general far below 500° C.